The present invention relates to devices and processes which are utilized to detect or limit positional errors with respect to the intended direction-of-track of a motor vehicle during maneuvering upon a road surface.
A number of apparatuses have been disclosed in prior art seeking to achieve the aforestated objective. For example, U.S. Pat. No. 3,719,246 BOTT discloses a machine which is comprised of a gyroscope, an array of sensors and actuators and a control circuit. The sensors and gyroscope are disposed about the structure of a motor vehicle in a manner which facilitates the gathering of data concerning the pitch, roll and yaw axes as well as the transverse velocity of the vehicle's tires and the steered direction of the front wheels. Forward velocity is also measured, along with the attendant position of the throttle plate. These parameters are introduced into the disclosed control circuit which selectively modulates throttle and braking responses to the vehicle's several wheels in response to an inferred sliding condition of the automobile, as dictated by one of three programs which is manually selected by the operator of the motor vehicle. In a similar manner, U.S. Pat. No. 5,247,466 SHIMADA et. al. discloses in his teaching a device which comprises G-sensors disposed about the structure of an automobile for the purpose of providing a transductive matrix from which an on-board computer may infer the tractive state of the subject vehicle and adjust the velocity of the automobile as necessary to avoid a sliding condition of same. U.S. Pat. No. 5,351,192 TSUYAMA et. al. also teaches in his disclosure an inference-type apparatus which utilizes a measuring system to quantify the lateral and rectilinear accelerations of a motor vehicle from the rotational differential of the vehicle's wheels for the purpose of estimating the associated road surface's resistance. With his arrangement, a sliding condition of the motor vehicle can be discerned by an on-board computer system based upon the factors of estimated road surface resistance and the vehicle's instant operational mode.
All of the aforementioned systems are not true positional detection devices and therefore must infer from the data gathered from a number of associated input devices when a motor vehicle has lost, or is about to lose, directional fidelity. As such, these machines must make fairly broad assumptions concerning the tractive state of the subject motor vehicle. These assumptions can lead to operational errors which, at the least, will narrow the envelope of the vehicle's handling potential, and quite possibly could lead to hazardous operational modes. Also, by their nature, the aforestated type of devices are very complex in terms of hardware and software and pose considerable practical difficulties in terms of adaptability of any one completed structure to another similar-type vehicle.